[gnome-games] gamepad-mappings-manager: Add a missing g_free()

[Adrien Plazas <aplazas src gnome org>]

commit a362a7d49c2c33ed3fbc2e7823e2418c35ce4735
Author: Adrien Plazas <kekun plazas laposte net>
Date:   Sat Aug 5 17:29:24 2017 +0200

    gamepad-mappings-manager: Add a missing g_free()
    
    This avoids a memory leak.

 src/gamepad/gamepad-mappings-manager.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/src/gamepad/gamepad-mappings-manager.c b/src/gamepad/gamepad-mappings-manager.c
index a43e95e..6e20de1 100644
--- a/src/gamepad/gamepad-mappings-manager.c
+++ b/src/gamepad/gamepad-mappings-manager.c
@@ -83,6 +83,7 @@ add_from_input_stream (GamesGamepadMappingsManager  *self,
       break;
 
     add_mapping (self, mapping_string);
+    g_free (mapping_string);
   }
   g_object_unref (data_stream);
 }